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Two new hexafluorogermanate dihydrates, viz. SrGeF6 ⋅ 2H2O and CaGeF6 ⋅ 2H2O, were synthesised from aqueous solutions; their crystal structures were refined in space group P21/n (SrGeF6 ⋅ 2H2O: a=5.9605(2) Å, b=9.6428(3) Å, a=10.9866(3) Å and β=99.1590(10), Z=4, 5122 refl., 104 param., R1=0.0195, wR2=0.0470; CaGeF6 ⋅ 2H2O: a=5.8472(5) Å, b=10.5099(9) Å, c=9.6267(9) Å and β=103.521(3), Z=4, 4756 refl., 101 param., R1=0.0224, wR2=0.0616). Upon doping with Eu2+ luminescence in the NUV regime was observed. The crystal structures of CaGeF6 and MgGeF6 could be solved and refined via Rietveld refinement from powder samples gained by thermal decomposition of the respective hydrates; both compounds adopt the LiSbF6 structure type (CaGeF6: a=5.4099(5) Å, c=13.9835(13) Å, Z=3, Rwp=0.0291, RBragg=0.0142; MgGeF6: a=5.1219(2) Å, c=13.0851(7), Z=3, Rwp=0.034, RBragg=0.01). Further, the luminescence of MgGeF6 ⋅ 6H2O:Eu2+, which emits light in the violet to blue regime, is reported.

Borosulfates consist of heteropolyanionic networks of corner-shared (SO

Borosulfates provide fascinating structures and properties that go beyond a pure analogy to silicates. Mg3[H2O→B(SO4)3]2 is the first borosulfate featuring a boron atom solely coordinated by three tetrahedra. Thus, the free Lewis acidic site forms a Lewis acid–base adduct with a water molecule. This is unprecedented for borosulfate chemistry and even for borates. Quantum chemical calculations on water exchange reactions with BF3 and B(C6F5)3 revealed a higher Lewis acidity for the borosulfate anion. Moreover, proton exchange reactions showed a higher Brønsted acidity than comparable silicates or phosphates. Additionally, Mg3[H2O→B(SO4)3]2 was characterised by X‐ray diffraction, infrared spectroscopy, thermogravimetric analysis, and density functional theory (DFT) calculations., The ever‐expanding chemistry of borosulfates is enriched by the novel borosulfate Mg3[H2O→B(SO4)3]2 featuring an unprecedented Lewis acid–base adduct of water to the anion [B(SO4)3]3−. Isodesmic exchange calculations revealed high Lewis and Brønsted acidity, opening new insights and perspectives for this fascinating silicate‐analogous material class.

The amidosulphates Mg(NH

Unconventional borosulfates containing S-O-S bridges are still rare. Sr[B2(SO4)3(S2O7)] was synthesized solvothermally in oleum (65% SO3) and crystallizes in a new structure type in space group P21/n (Z = 4, a = 747.0(2) pm, b = 1533.4(4) pm, c = 1222.0(3) pm, β = 93.293(10)°). The structure features loop-branched vierer double chains, in which two terminal sulfate tetrahedra are condensed to a disulfate group. The resulting ratio between boron and sulfur of 2:5 was not yet found in borosulfate chemistry. The presence of S-O-S bridges was confirmed by FT-IR spectroscopy. Temperature-programmed X-ray powder diffraction in addition to thermogravimetric analysis revealed a transformation from chains containing S-O-S bridges in Sr[B2(SO4)3(S2O7)] to chains containing solely B-O-S bridges in Sr[B2(SO4)4] and to chains containing B-O-B bridges in Sr[B2O(SO4)3].

Increased synthetic control in borosulfate chemistry leads to the access of various new compounds. Herein, the polymorphism of phyllosilicate-analogous borosulfates is unraveled by adjusting the oleum (65 % SO3) content. The new polymorphs beta-Mg[B-2(SO4)(4)] and alpha-Co[B-2(SO4)(4)] both consist of similar layers of alternating borate and sulfate tetrahedra, but differ in the position of octahedrally coordinated cations. The alpha-modification comprises cations between the layers, whereas in the beta-modification cations are embedded within the layers. With this new synthetic approach, phase-pure compounds of the respective polymorphs alpha-Mg[B-2(SO4)(4)] and beta-Co[B-2(SO4)(4)] were also achieved. Tanabe-Sugano analysis of the Co(2+)polymorphs reveal weak ligand field splitting and give insights into the coordination behavior of the two-dimensional borosulfate anions for the first time. DFT calculations confirmed previous in silico experiments and enabled an assignment of the polymorphs by comparing the total electronic energies. The compounds are characterized by single-crystal XRD, PXRD, FTIR, and UV/Vis/NIR spectroscopy, thermogravimetric analysis (TGA), and density functional theory (DFT) calculations.

Various different possible connection patterns of sulfate and borate tetrahedra enable a vast structural diversity in borosulfates, a rather new class of silicate-analogous compounds. Here we unravel a direct relationship from S-O-S to B-O-S to B-O-B bridges for the first time in borosulfate chemistry. Solvothermal synthesis in pure oleum (65% SO3) yielded the first alkaline earth metal borosulfate comprising S-O-S bridges: Ba[B(S2O7)2]2 (I2/a, Z = 4, a = 1160.77(9) pm, b = 891.44(7) pm, c = 2130.26(19) pm, β = 104.0341(17)°) contains molecular [B(S2O7)2]- anions of a central boron atom and two chelating disulfate groups. By using equal amounts of sulfuric acid and oleum solely B-O-S bridges were obtained in Ba[B2(SO4)4] (Pnna, Z = 4, a = 1279.08(18) pm, b = 1280.0(2) pm, c = 731.70(11) pm) featuring one-dimensional ∞1[B(SO4)4/2]- chains. The thermal analysis on Ba[B(S2O7)2]2 revealed the conversion from S-O-S bridges to B-O-S bridges in Ba[B2(SO4)4] and to B-O-B bridges in Ba[B2O(SO4)3] by a successive release of SO3. Thus, BaO-B2O3-SO3 is the first quaternary system for borosulfates uniting all three possible connection patterns enabling us to understand the fascinating but systematic chemistry in such systems. Both new compounds were also characterized by means of X-ray powder diffraction, electrostatic calculations, and infrared spectroscopy assisted by density functional theory (DFT).

The host structure of the new phosphor Sr6(BO3)3BN2:Eu2+ crystallizes tetragonally (Sr6(BO3)3BN2, P42/mbc, Z = 8, a = 12.8173(3) A, b = 14.0740(5) A, Rint = 0.037, R1 = 0.052, and wR2 = 0.121) and ...

Pb 5 O 2 [ WO 6 ] ${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{WO}}_{6}\right]$ was discovered as a frequently observed side phase during our investigation on lead tungstates. Its crystal structure was solved by single-crystal X-ray diffraction ( P 2 1 / n $P{2}_{1}/n$ , a = 7.4379 ( 2 ) $a=7.4379\left(2\right)$ Å, b = 12.1115 ( 4 ) $b=12.1115\left(4\right)$ Å, c = 10.6171 ( 3 ) $c=10.6171\left(3\right)$ Å, β = 90.6847 ( 8 ) $\beta =90.6847\left(8\right)$ °, Z = 4 $Z=4$ , R int = 0.038 ${R}_{\text{int}}=0.038$ , R 1 = 0.020 ${R}_{1}=0.020$ , ω R 2 = 0.029 $\omega {R}_{2}=0.029$ , 4188 data, 128 param.) and is isotypic with Pb 5 O 2 [ Te 6 ] ${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{Te}}_{6}\right]$ . Pb 5 O 2 [ WO 6 ] ${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{WO}}_{6}\right]$ comprises a layered structure built up by non-condensed [WO6] 6 − ${}^{6-}$ octahedra and [ O 4 Pb 10 ] 12 + ${\left[{\text{O}}_{4}{\text{Pb}}_{10}\right]}^{12+}$ oligomers. The compound was characterised by spectroscopic measurements (Infrared (IR), Raman and Ultraviolet–visible (UV/Vis) spectra) as well as quantum chemical and electrostatic calculations (density functional theory (DFT), MAPLE) yielding a band gap of 2.9 eV fitting well with the optical one of 2.8 eV. An estimation of the refractive index based on the Gladstone-Dale relationship yielded n ≈ 2.31 $n\approx 2.31$ . Furthermore first results of the thermal analysis are presented.

Three new members in the Bi

Two polymorphs of the borosulfate Cu[B

Reaction of Cu2[(OH)2CO3], H3BO3 and oleum yields either inosilicate-analogous α-Cu[B2(SO4)4] or the new phyllosilicate-analogous β-Cu[B2(SO4)4], both subject to Jahn–Teller distortion; two polymorphs of Cu(HSO4)2 and Cu[S2O7] are also reported.

Alkaline-earth amidosulphates and their hydrates provide not only a fascinatingly rich crystal chemistry but also an unprecedented and straightforward synthetic approach to sulphur nitride, i.e. S4N4.

The phyllosilicate-analoguous borosulfate H2[B2(SO4)4] and its cadmium salt, Cd[B2(SO4)4], have been synthesized via various paths and analyzed thoroughly. The heteropolyacid is the second structurally determined acid within borosulfate chemistry.

The quaternary halide-containing yttrium(iii) oxidoantimonates(iii) YSb

We report the crystal structures of two tin(IV) sulfate polymorphs Sn(SO4)2-I (

H. A. H. and P. N. thank the Deutsche Forschungsgemeinschaft (DFG) for financial support under the project HO 4503/5-1. We report the crystal structures of two tin(iv) sulfate polymorphs Sn(SO4)2-I (P21/c (no. 14), a = 504.34(3), b = 1065.43(6), c = 1065.47(6) pm, β = 91.991(2)°, 4617 independent reflections, 104 refined parameters, wR2 = 0.096) and Sn(SO4)2-II (P21/n (no. 14), a = 753.90(3), b = 802.39(3), c = 914.47(3) pm, β = 92.496(2)°, 3970 independent reflections, 101 refined parameters, wR2 = 0.033). Moreover, the first heterovalent tin sulfate Sn2(SO4)3 is reported which adopts space group P̄ (no. 2) (a = 483.78(9), b = 809.9(2), c = 1210.7(2) pm, α = 89.007(7)°, β = 86.381(7)°, γ = 73.344(7)°, 1602 independent reflections, 152 refined parameters, wR2 = 0.059). Finally, SnSO4 – the only tin sulfate with known crystal structure – was revised and information complemented. The optical and thermal properties of all tin sulfates are investigated by FTIR, UV-vis, luminescence and 119Sn Mössbauer spectroscopy as well as thermogravimetry and compared. Postprint

Ammonium bis(biureto)borate, NH4[B(biu)2] (biu = NH–(C═O)–NH–(C═O)–NH), was synthesized as a phase pure powder from urea and triethylborate in a sophisticated solvothermal process. Its crystal stru...

Unconventional borosulfates containing S-O-S bridges are still rare. Sr[B

Various different possible connection patterns of sulfate and borate tetrahedra enable a vast structural diversity in borosulfates, a rather new class of silicate-analogous compounds. Here we unravel a direct relationship from S-O-S to B-O-S to B-O-B bridges for the first time in borosulfate chemistry. Solvothermal synthesis in pure oleum (65% SO

The first bismuth borosulfate (H3O)Bi[B(SO4)2]4 is only the second featuring a three‐dimensional anion, the first tectosilicate‐analogous borosulfate synthesised solvothermally without a precursor (from Bi(NO3)3⋅5 H2O and B(OH)3 in oleum); moreover, it is the first comprising two differently charged cations and crystallises in a new structure type in space group I4‾ (no. 82) (a=11.857(1), c=8.149(1) Å, 1947 refl., 111 param., wR2=0.037), confirmed by a second harmonic generation (SHG) measurement. The B(SO4)4 supertetrahedra are connected via all four sulfate tetrahedra resulting in a three‐dimensional anion with both H3O+ and Bi3+ cations in channels. Additionally, the crystal structure of a further bismuth borosulfate, Bi2[B2(SO4)6], is elucidated crystallising isotypically to the rare‐earth borosulfates R2[B2(SO4)6] in space group C2/c (No. 15) (a=13.568(2), b=11.490(2), c=11.106(2) Å, 3127 refl., 155 param., wR2=0.035). Moreover, the optical and thermal properties of both compounds are discussed., The first tectosilicate‐analogous oxonium–bismuth borosulfate obtained from the reaction of oleum with bismuth nitrate and boric acid decomposes to the first bismuth borosulfate—a ring‐silicate‐analogous one—delivering exciting insights in the chemistry and the crystal structures of this still expanding material class.

Increased synthetic control in borosulfate chemistry leads to the access of various new compounds. Herein, the polymorphism of phyllosilicate‐analogous borosulfates is unraveled by adjusting the oleum (65 % SO3) content. The new polymorphs β‐Mg[B2(SO4)4] and α‐Co[B2(SO4)4] both consist of similar layers of alternating borate and sulfate tetrahedra, but differ in the position of octahedrally coordinated cations. The α‐modification comprises cations between the layers, whereas in the β‐modification cations are embedded within the layers. With this new synthetic approach, phase‐pure compounds of the respective polymorphs α‐Mg[B2(SO4)4] and β‐Co[B2(SO4)4] were also achieved. Tanabe–Sugano analysis of the Co2+ polymorphs reveal weak ligand field splitting and give insights into the coordination behavior of the two‐dimensional borosulfate anions for the first time. DFT calculations confirmed previous in silico experiments and enabled an assignment of the polymorphs by comparing the total electronic energies. The compounds are characterized by single‐crystal XRD, PXRD, FTIR, and UV/Vis/NIR spectroscopy, thermogravimetric analysis (TGA), and density functional theory (DFT) calculations., Controlling polymorphism: Sophisticated synthesis strategies enable a targeted access to different polymorphs in M[B2(SO4)4] (M=Mg, Co). Both polymorphs comprise phyllosilicate‐analogous topology with corner‐sharing borate and sulfate tetrahedra and differ in the position of the octahedrally coordinated cations. Tanabe–Sugano analysis of the UV/Vis/NIR spectra of α‐ and β‐Co[B2(SO4)4] revealed a weak ligand field splitting of the borosulfate anion.

The pentasodium rare-earth tungstates Na5M(WO4)4 are closely related to the sodium rare-earth double tungstates Na5M(WO4)2 both adopting the scheelite structure type (space group I41/a, no. 88). After the preparation of polycrystalline powders via flux syntheses improving the phase purity significantly, the crystal structures of Na5M(WO4)4 (M = Y, La-Nd, Sm-Lu, Bi) were determined by single crystal XRD and Rietveld analysis. Na5M(WO4)4 is a promising phosphor material both as a host and as a 100% phosphor due to the possible charge transfer of the tungstate group and the absence of any concentration quenching. Na5M(WO4)4 incongruently melts to Na5M(WO4)2 and Na2WO4. After the clarification of the crystallographic relationship of Na5M(WO4)4 and Na5M(WO4)2 based on a rare isomorphic transition of index 5 (i5) the non-linear trend of the decomposition temperature within the row of rare earth ions is explained systematically taking into account the existence of domains within the crystal structure predetermining the posterior decomposition. A miscibility gap for solid solutions of Na5Y(WO4)4 and Na5Eu(WO4)4 or Na5Tb(WO4)4 is identified and its temperature dependence is investigated. Furthermore, the investigation of the fluorescent properties of Na5M(WO4)4 (M = Pr, Sm, Eu, Tb, Tm, Bi), Na5Y1-xEux(WO4)4 and Na5Y1-yTby(WO4)4 provided insights into the weak ligand field and the energy transfer from WO42- to M3+ governed by the emission of the sensitiser within Na5M(WO4)4. Additionally, the compounds were characterised by magnetic measurements and vibrational, UV/Vis and 151Eu Mössbauer spectroscopy.

The synthesis and crystal structure of the perfluorinated metal–organic framework CFA-15 (Coordination Framework Augsburg University-15), CuII3(tfpc)2(OH)2·DMF, as well as the crystal structure of its ligand (H2-tfpc = 3,5-bis(trifluoromethyl)-1H-pyrazole-4-carboxylic acid) are described. The MOF crystallizes in the monoclinic crystal system within the chiral space group C2 (no. 5). It features a 3-D microporous framework with rhombic channels along the c-axis. The MOF is formed by 1-D chains of Cu(II) ions expanding in the c-direction, bridged by OH− groups, DMF molecules and tfpc2− ligands. Two different Cu(II) species are located within the structure, bridged in a {Cu1–Cu1–Cu2–Cu1–Cu1–Cu2} mode. By thermal treatment, it was possible to remove coordinated solvent molecules and generate free accessible, unsaturated and reactive metal centres. The structure of activated CFA-15 was refined via Rietveld method. DRIFT measurements, which were used to study adsorption of CO2 and NO in the MOF, showed a formation of a stable NO-CFA-15 complex. CFA-15 was further characterized by thermogravimetric analysis, variable temperature powder X-ray diffraction measurements, IR spectroscopy, as well as photoluminescence and gas sorption measurements. The isosteric heats of adsorption for CO, CO2, H2 and O2 were determined, and compared to DFT calculated sorption energies as well as to data reported in literature for similar materials.

Aside from amorphous phases, only a single crystalline tin borate had been synthesised so far under high pressure. In this work, we present the very first crystalline ternary tin borate Sn3B4O9 synthesised under ambient pressure by decomposition of Sn3[B3O7]F above 500 °C. The crystal structure of Sn3B4O9 (P21/c, Z = 4, a = 768.07(3) pm, b = 1206.78(4) pm, c = 924.96(3) pm, β = 101.847(1)°, 10 550 data, 147 parameters, R1 = 0.028) determined by single-crystal X-ray diffraction comprises open layered borate polyanions with Sn(II) ions in-between showing the presence of a stereochemically active lone pair. Sn3B4O9 was further characterized by DFT calculations and vibrational spectroscopy. Its optical band gap was calculated to approx. 3.5(1) eV. Tin borate was gained by thermal decomposition of Sn[B2O3F2] via a further new tin borate fluoride Sn2[B7O12]F (C2/c, Z = 8, a = 1037.99(2) pm, b = 859.78(2) pm, c = 2370.71(8) pm, β = 93.5650(10)°, 2674 data, 199 parameters, R1 = 0.045).

Recently, sulfates have attracted attention as materials for non-linear optical applications. This compound class is extended by Tb(HSO4)(SO4), which is solvothermally synthesised from Tb4O7 and sulfuric acid. The compound crystallises in the non-centrosymmetric space group P21 (Z = 2, a = 665.03(5) pm, b = 659.41(5) pm, c = 680.24(5) pm, and β = 104.640(2)°) and is homeotypic with Ni2In. The terbium ions adopt the indium sites and the sulfate and hydrogen sulfate anions are situated on the nickel sites. The compound shows green luminescence based on f-f-transitions and the positions of the f-d-excitation bands reveal a weak coordination behaviour of the sulfate anions. Tb(HSO4)(SO4) exhibits a second harmonic generation response comparable to KH2PO4 (KDP). Furthermore, the material is characterised by electrostatic calculations, infrared spectroscopy and thermal analysis.

Crystalline orthorhombic rare earth carbonate hydroxides Ln[CO3][OH] (Ln=La, Pr, Nd, Sm, Eu, Gd) were synthesised as phase pure powders via a simple hydrothermal reaction. CO2 from air acted as natural carbonate source and cetyltrimethylammonium bromide was added as templating agent to an aqueous rare earth nitrate solution. Single-crystal X-ray structure determination was performed on La[CO3][OH] (Pnma, a=7.4106(5), b=5.0502(3), c=8.5901(6) Å, 563 independent reflections, 38 refined parameters, wR2=0.037), Pr[CO3][OH] (Pnma, a=7.2755(4), b=4.9918(3), c=8.5207(5) Å, 744 independent reflections, 38 refined parameters, wR2=0.04), Eu[CO3][OH] (Pnma, a=7.1040(4), b=4.8940(3), c=8.4577(5) Å, 1649 independent reflections, 38 refined parameters, wR2=0.05) and Gd[CO3][OH] (Pnma, a=7.069(7), b=4.874(5), c=8.464(9) Å, 431 independent reflections, 38 refined parameters, wR2=0.051). These findings are supported by powder XRD, infrared spectroscopy, UV/Vis spectroscopy and, for Pr[CO3][OH] and Eu[CO3][OH], by measurements of the non-linear optical properties. Thermal analysis could demonstrate the possible use of the Ln[CO3][OH] phases as precursors for rare earth carbonate dioxides Ln 2[CO3]O2 and rare earth oxides Ln 2O3. The decomposition products inherit the precursor’s morphology. The lattice parameters of Pr2[CO3]O2 were refined from high-temperature powder XRD data.

Several alkali and alkaline earth (iso)cyanurates were synthesized by simple aqueous acid-base reactions and aqueous salt metathesis reactions, respectively, yielding nine new structure types. Single-crystals could be grown and the crystal structures of Rb[H2C3N3O3]·H2O-I, Rb[H2C3N3O3]·H2O-II, Cs[H2C3N3O3]·0.5H2O, Sr[H2C3N3O3]2·4H2O, Ba3[H2C3N3O3]2[HC3N3O3]2·4H2O, Ca[HC3N3O3]·3.5H2O, Sr[HC3N3O3]·3H2O, Sr[HC3N3O3]·2H2O, and Sr2[C3N3O3]OH were elucidated by single-crystal XRD. Rb3[H2C3N3O3]3[H3C3N3O3]·4H2O, Cs[H2C3N3O3]·0.5H2O, and Sr[HC3N3O3]·2H2O were synthesized as phase pure, crystalline powders and were further characterized by powder XRD, FT-IR spectroscopy, UV/Vis spectroscopy, and thermogravimetry. Sr[HC3N3O3]·2H2O was shown to be an air- and water-resistant, cheap and easily obtained precursor for the phase-pure synthesis of Sr3[C3N3O3]2, a promising SHG material, and Sr[NCN]. Moreover, an interesting dependence of the polymeric anion structure from its protonation degree was observed.

The lanthanide(III) chloride oxidotungstates(VI) with the formula Ln3Cl3[WO6] for Ln = La - Nd, Sm - Tb were synthesized by solid-state reactions utilizing the respective lanthanide trichloride, lanthanide sesquioxide (where available), and tungsten trioxide together with lithium chloride as flux. The title compounds crystallize hexagonally in space group P63/m (no. 176, a = 941 - 909, c = 543 - 525 pm, Z = 2). The structures comprise crystallographically unique Ln3+ cations surrounded by six O2- and four Cl- anions (C.N. = 10) forming distorted tetracapped trigonal prisms as well as rather uncommon trigonal prismatic [WO6]6- units whose edges are coordinated by nine Ln3+ cations. Thus, a □(3¦∞){([WO6]Ln□(e¦(9/3)))3+} framework (e = edge-sharing) is created, which contains tube-shaped channels along [001] lined with chloride anions. To elucidate the spectroscopic and magnetic properties of the obtained pure phase samples, single-crystal Raman (for Ln = La - Nd, Sm-Tb), diffuse reflectance (for Ln = La, Pr, Nd, Gd) and luminescence spectroscopy (for bulk Ln3Cl3[WO6] (Ln = La, Eu, Gd, Tb) and Eu3+- or Tb3+-doped derivatives of La3Cl3[WO6] and Gd3Cl3[WO6], respectively) were performed and their temperature-dependent magnetic moments (for Ln = Pr, Nd, Gd) were determined.

(NH4)2[B2P3O11(OH)] was synthesized as a crystalline colorless powder by reaction of (NH4)2HPO4, H3BO3, and H3PO4 under hydrothermal conditions at 180 °C. According to X-ray single-crystal investigations (NH4)2[B2P3O11(OH)] crystallizes in a new structure type in the orthorhombic space group P212121 (no. 19) [Z = 4, a = 4.509(3), b = 14.490(11), c = 16.401(12) A, R1 = 0.046, wR2 = 0.093, 1682 data, 200 parameters]. The crystal structure comprises infinite layers of corner-sharing borate, phosphate and hydroxo-phosphate tetrahedra with ammonium ions in-between. The loop-Branched (lB) zweier-single layer reveals an open-Branched (oB) vierer-single ring as fundamental building unit (FBU), which was observed in (NH4)2MnII[B2P3O11(OH)2]Cl[1] for the first time. Besides the spectroscopic properties the thermal behavior is presented as well.

The pentasodium rare-earth tungstates Na5M(WO4)4 are closely related to the sodium rare-earth double tungstates Na5M(WO4)2 both adopting the scheelite structure type (space group I41/a, no. 88). After the preparation of polycrystalline powders via flux syntheses improving the phase purity significantly, the crystal structures of Na5M(WO4)4 (M = Y, La–Nd, Sm–Lu, Bi) were determined by single crystal XRD and Rietveld analysis. Na5M(WO4)4 is a promising phosphor material both as a host and as a 100% phosphor due to the possible charge transfer of the tungstate group and the absence of any concentration quenching. Na5M(WO4)4 incongruently melts to Na5M(WO4)2 and Na2WO4. After the clarification of the crystallographic relationship of Na5M(WO4)4 and Na5M(WO4)2 based on a rare isomorphic transition of index 5 (i5) the non-linear trend of the decomposition temperature within the row of rare earth ions is explained systematically taking into account the existence of domains within the crystal structure predetermining the posterior decomposition. A miscibility gap for solid solutions of Na5Y(WO4)4 and Na5Eu(WO4)4 or Na5Tb(WO4)4 is identified and its temperature dependence is investigated. Furthermore, the investigation of the fluorescent properties of Na5M(WO4)4 (M = Pr, Sm, Eu, Tb, Tm, Bi), Na5Y1−xEux(WO4)4 and Na5Y1−yTby(WO4)4 provided insights into the weak ligand field and the energy transfer from WO42− to M3+ governed by the emission of the sensitiser within Na5M(WO4)4. Additionally, the compounds were characterised by magnetic measurements and vibrational, UV/Vis and 151Eu Mossbauer spectroscopy.

The fluorooxoborates Sr[B5O7F3] (Ccm21 (no. 36), Z = 4, a = 864.777(3) pm, b = 1001.037(4) pm, c = 810.110(5) pm, 630 refl., 68 param., R F = 0.061, R Bragg = 0.051) and Sr[B5O7F3]:Eu2+ were synthesized via solid-state reactions from Sr(BF4)2 and B2O3. Doping was achieved by adding EuF3, which was reduced to its divalent state during the synthesis. Sr[B5O7F3] was investigated by infrared spectroscopy. Photoluminescence spectra of the doped compound revealed an Eu2+ 5d-4f emission in the UV regime peaking at 371 nm with a full width at half maximum (FWHM) of 21 nm upon excitation at 239 nm, which proves a weak coordination of europium by the anionic fluorooxoborate network.

Borosulfates are oxoanionic compounds consisting of condensed sulfur‐ and boron‐centered tetrahedra. Hitherto, they were mostly achieved from solvothermal syntheses in SO3‐enriched sulfuric acid, or from reactions with the superacid H[B(HSO4)4]. The crystal structures are very similar to those of the corresponding class of silicates and their substitution variants, especially regarding the typical structural motif of corner‐sharing tetrahedra. However, the borosulfates are supposed to be even more versatile, because (BO3) units might also be part of the anionic network. The following article deals with detailed reports on the different synthesis strategies, the crystal chemistry of borosulfates in comparison to silicates, and their hitherto identified properties., Borosulfates are structurally similar to silicates. Their anionic subunits consist of alternating (SO4) and (BO4) tetrahedra forming oligomers, single and multiple chains, layers and extended 3D network structures. The review deals with detailed reports on the different synthesis strategies, the crystal chemistry of borosulfates in comparison to silicates, and their hitherto identified properties.

Recently, sulfates have attracted attention as materials for non-linear optical applications. This compound class is extended by Tb(HSO

The lanthanide(III) chloride oxidomolybdates(VI) with the empirical formula Ln

The rare earth borosulfates RE2[B2(SO4)6] with RE = Y, La-Nd, Sm, Eu and Tb-Lu were synthesised under solvothermal conditions starting from the metal chlorides (Pr, Nd, Eu), the metal oxides (Y, La, Ce, Sm, Tb, Dy, Er, Tm, Lu), or the metal powders (Ho, Yb). They crystallize isotypically with Gd2[B2(SO4)6] in space group C2/c (Z = 4, a = 1346.9(3)-1379.24(17) pm, b = 1136.4(3)-1158.87(14) pm, c = 1079.9(3)-1139.54(14) pm, β = 93.369(8)-93.611(4)°). The anionic structure consists of an open-branched vierer single ring {oB, 1r}[B2S2O12(SO3)4]6-, similar to the mineral eakerite (Ca2Al2Sn[Si6O18](OH)2·2H2O) which contains {oB, 1r}[Si4O12(SiO3)2]12- moieties. The fluorescence spectroscopy of the samples with RE = Ce, Eu and Tb features emissions in the deep UV, the red, and the green part of the spectrum and furthermore revealed a weak coordination behaviour of the borosulfate anion. Thermal analysis of Eu2[B2(SO4)6] showed the highest thermal stability observed for borosulfates so far; respective trends within the borosulfate family are discussed. Additionally, the compounds were characterised by magnetic measurements, vibrational and 151Eu Mößbauer spectroscopy.

NaMg[PO3S]·9H2O was obtained as single-phase crystalline powder starting from NaOH, PSCl3 and MgCl2·6H2O. At room temperature NaMg[PO3S]·9H2O crystallises in space group Cmc21 (no. 36) (a=638.58(4) pm, b=1632.31(10) pm, c=1217.16(7) pm, Z = 4; Rint = 0.032, Rσ = 0.034, R1 = 0.036, wR2 = 0.071). The data collection at 100 K reveals an ordering of the PO3S tetrahedra by undergoing a symmetry reduction to P21 (no. 4) and an according formation of twins (C1121, unconv. setting of P21, a=631.41(3) pm, b=1630.00(7) pm, c=1219.24(5) pm, γ=90.00(2)°, Z = 4; Rint = 0.115, Rσ = 0.064, R1 = 0.045, wR2 = 0.070). NaMg[PO3S]·9H2O comprises isolated PO3S tetrahedra, distorted MgO6 octahedra and trigonal NaO6 prisms. 31P NMR spectroscopy showed a chemical shift of 33.7 ppm. The vibrational spectra of NaMg[PO3S]·9H2O were recorded and the relevant bands were assigned.

The lanthanide(III) chloride oxidomolybdates(VI) with the empirical formula Ln3Cl3[MoO6] (Ln = La, Pr, and Nd) were synthesized by solid-state reactions utilizing the respective lanthanide trichlor...

The rare earth borosulfates RE2[B2(SO4)6] with RE = Y, La–Nd, Sm, Eu and Tb–Lu were synthesised under solvothermal conditions starting from the metal chlorides (Pr, Nd, Eu), the metal oxides (Y, La, Ce, Sm, Tb, Dy, Er, Tm, Lu), or the metal powders (Ho, Yb). They crystallize isotypically with Gd2[B2(SO4)6] in space group C2/c (Z = 4, a = 1346.9(3)–1379.24(17) pm, b = 1136.4(3)–1158.87(14) pm, c = 1079.9(3)–1139.54(14) pm, β = 93.369(8)–93.611(4)°). The anionic structure consists of an open-branched vierer single ring {oB, 1r}[B2S2O12(SO3)4]6−, similar to the mineral eakerite (Ca2Al2Sn[Si6O18](OH)2·2H2O) which contains {oB, 1r}[Si4O12(SiO3)2]12− moieties. The fluorescence spectroscopy of the samples with RE = Ce, Eu and Tb features emissions in the deep UV, the red, and the green part of the spectrum and furthermore revealed a weak coordination behaviour of the borosulfate anion. Thermal analysis of Eu2[B2(SO4)6] showed the highest thermal stability observed for borosulfates so far; respective trends within the borosulfate family are discussed. Additionally, the compounds were characterised by magnetic measurements, vibrational and 151Eu Mosbauer spectroscopy.